Vacuum-pan



3 Sheets-Sheet 1.

HI HI VACUUM PAN.

(No Model.)

No. 554,916. Patented-Feb. 18, 1896.

- FIEnI WITNESSES,

AWN/U) (No Model. 3 Sheets-Sheet 2.

H. H. DOW. VAGUUM PAN.

No. 554,916. Patented Feb. 18, 1896.

WITNESSES, I v m 7 M d/JAXZ 5355 (No Model.) 3 Sheets-Sheet 3 H. H. DOW.

VACUUM PAN.

No. 554,916. Patented Feb. 18, 1896.

FlG-DI MIND! LGRAHAM. PPIOTO'UTNO.WASNING\'DN.DG

UNITED STATES ATENT OFFICE,

HERBERT II. DOlV, OF MIDLAND, MICHIGAN, ASSIGNOR TO THE MIDLAND CHEMICAL COMPANY, OF CLEVELAND, OHIO.

VACUUM-PAN.

SPECIFICATION forming part of Letters Patent No. 554,916, dated February 18, 1896.

Application filed June 13, 189 5 Serial N0- 5 52,653 (N0 model.)

To all whom it may concern:

Be it known that I, HERBERT II. 'DOVV, a citizen of the United States, and a resident of Midland, county of Midland, and State of Michigan, have invented certain new and useful improvements in apparatus for producing granular salt or similar solid substances from liquids by evaporation, of which the fol lowing is a specification, the principle of the invention being herein explained, and the best mode in which I have contemplated applying that principle, so as to distinguish it from other inventions.

The annexed drawings and the following description set forth in detail one mode of carrying out the invention, such specific mode being but one of various ways in which the principle of the invention may be used.

In said annexed drawings, Figure I represents a View, partly in section, of my evaporating apparatus; Fig. II, a top plan view of the heater and the pan; and Fig. III, a view, partly in section, of the double-elfect apparatus.

An open heating-tank A has a steam-inlet A at one end and a steam-outlet A at the other end, which inlet and outlet, respectively, communicate with steam-spaces aand a at the ends of the tank. The steam-spaces are connected by tubes a by means of which the contents of the tank may be heated. A vacuum-chamber B is arranged above the heating-tank and is connected in any suitable or desired manner to a steam-separator B and to a condenser and air-pump B A pipe 1) extends from the vacuum-chamber to the heating-tank, so that the heated contents of said tank may rise in said pipe and enter the vacuumchamber. A pipe 5 extends from the bottom of the vacuum-chamber to a settling-tank C, so that the contents of said vacuum-chamberbrine containing salt in suspension-may descend into said tank. The settling-tank is substantially V-shaped in section and has a conveyer C in its bottom for conveying the settled salt to one end of the tank, and a belt-conveyer C against one inclined side of the tank and at the end of said other conveyer, whereby the settled salt may be removed from the tank after it has been conveyed to one end of the same.

A pipe 0 extends from near the open top of the settling-tank to near the open top of the heating-tank, whereby communication between said tanks is established. A supplypipe D has its discharge-opening over the settling-tank, and is provided with a cock d, operated by a float d, which opens the cock when the level of the contents of the tank falls and closes the cock when thelevel rises.

This apparatus is principally intended for the evaporation of salt brine, but maybe used equally well for the evaporation of sugar-sirup or any other liquid.

When'the apparatus is started, the heatingtank is filledwith brine, and steam is admitted into the steam spaces and pipes, heating the brine to such temperature that gypsum and kindred impurities will precipitate upon the heating-tubes in the open heating-tank, where they may easilybe removed by knocking upon said tubes without interrupting the operation of the apparatus, while the salt will remain in solution in the brine. The vacuum separating-chamber will cause the heated brine to ascend, and the water, in the form of steam, will be separated from the salt in said chamber and condensed, so that the concentrated brine with salt crystals in suspension will descend into the settling-tank, where the salt crystals will separate and settle to the bottom of the tank to be collected and removed by the conveyers. The brine from which all'the salt has not yet been removed will flow back into the heating-tank through the pipe which connects the heating and settling tanks.

In this apparatus the brine is only heated in the open heating-tank, from which the gypsum and other precipitated impurities may be removed without interruption of the process. Gypsum is less soluble in hot brine than in cold brine, and will therefore deposit in the vessel to which heat is applied. Salt, on the contrary, is more soluble in hot brine than in cold brine, and will therefore remain in solution until the dissolving-water is removed at a lower temperature in the vacuumchamber in the form of steam and by means of the condenser and air-pump. The brine will continually circulate, deposit salt in the settling-tank, and will be replenished from the supply-pipe.

In vacuum apparatus usually employed in the manufacture of salt the heat is applied to the vacuum-chamber. This will cause the gypsum and other impurities in the brine to be deposited in said chamber, which will necessitate the interruption of the process for the purpose of cleaning the heating-surfaces from the deposits thereon.

In apparatus employing open pans the gypsum will either settle with the salt or Will be deposited upon the heating-surfaces of the pan and thus interfere with the proper heating of the pans.

In Fig. III a double-effect apparatus is illustrated. The parts of this apparatus are the same as in the single-effect apparatus, the only change being that the parts are duplicated, and that the steam-supply for one heating-tank is taken from the exhaust of the other vacuum separating chamber. The brine is fed into the settling-tank for the hi ghvacuum and low-temperature apparatus and passes from said tank to the heating-tank of said apparatus, from which as much as is re quired of it passes to the heating-tank of the low-vacuum and high-temperature apparatus. For the purpose of distinguishing the two apparatus the high-vacu um and low-temperature apparatus is marked No. 1 in the drawings and the low-vacuum and high-temperature apparatus is marked No. 2. The operation of each apparatus is the same as of the single-eifect apparatus. The steam from the low-vacuum and high-temperature vacuum-chamber is conducted by a pipe 11 to the heating-tank of the high-vacuum and lowtemperature apparatus, where it heats the brine and is then drawn oil by a vacuumpump B In this manner heat is saved in the apparatus, as it is only necessary to supply steam to the heating-tank of the lowvacuum and hi gh-temperature apparatus, and the efliciency of the apparatus is increased.

Other modes of applying the principle of my invention may be employed for the mode herein explained. Change may therefore be made as regards the steps herein set forth, provided the principles of operation set forth respectively in the following claim are employed.

I therefore particularly point out and distinctly claim as my invention In apparatus for producing granular salts or similar solid substances from liquids by evaporation, the combination of an open heating-vessel provided with means for heating the liquid therein and thereby separating and depositing the less soluble impurities accessible for removal, an elevated separatingvessel having a pipe ascending into it from the heating-vessel and havinga descending pipe from its bottom, means for reducing the atmospheric pressure in said separating-Vessel to raise the liquid from the heating-vessel into the separating-vessel and to produce evaporation without the application of heat to said latter vessel, and a settling-vessel having the descending pipe opening into it and from which the settled solids may be re- 1noved, substantially as set forth.

I11 testimony that I claim the foregoing to be my invention I have hereunto set my hand this 22d day of May, A. D. 1895.

HERBERT II. DOW. \Vitnesses DAVID I. DAVIES, WM. Snonnn. 

